A family of 3 is planning on taking ski lessons The cost of renting a pair of skis per hour, x, can be represented by the function g(x)=12+3x

The cost for ski lessons for a small group can be represented by the function f(x)=20x where x is the number of hours.

Write a function rule to represent the total cost for the lesson as a function of the number of hours. Assume all 3 will need to rent skis.